Mammary adenocarcinoma is the most common cancer among women in the United States, with an estimated 175,000 new cases occurring in 1993. Currently, one out of nine American women will develop breast cancer in her lifetime. The rate of breast cancer incidence has increased 2-3% per year over the past decade in both premenopausal and postmenopausal women. Breast cancer is the second major cause of cancer deaths in women, and approximately 45,000 deaths from breast cancer are anticipated in 1993. The integration of basic science research with clinical investigations is critical in addressing key issues in breast cancer etiology and therapy. The P20 Program Development Grant on Breast Cancer focuses on molecular targets In breast cancer etiology and therapy and will involve two centers here at The Ohio State University. The OSU Comprehensive Cancer Center (OSUCCC) and the Center's Arthur G. James Cancer Hospital and Research Institute (CHRI) provide important opportunities for multidisciplinary laboratory and clinical research interactions in breast cancer. The Center for Molecular Environmental Health (CMEH) at The Ohio State University emphasizes research in molecular toxicology, molecular epidemiology, and molecular pathology. Furthermore, a core of key faculty and researchers in the OSUCCC, the CMEH, and associated Colleges of Medicine, Pharmacy, Veterinary Medicine, and Biological Sciences are committed to breast cancer research and the development of translational studies in breast cancer. The nucleus of investigators of this P20 Program Development Grant on Breast Cancer are involved in several OSUCCC Basic Sciences (Hormones and Cancer, Carcinogenesis, Therapeutics, Gene Expression) and Clinical Programs (Surgical Oncology, Hematology/Oncology). Research strengths in areas of endocrinology, developmental therapeutics, gene expression, and carcinogenesis permit unique opportunities for integration of this research into new programs focusing on translational research objectives in breast cancer etiology and therapy. The overall theme of the P20 Program Development Grant addresses molecular targets In breast cancer etiology and therapy. The research projects center around the interactions of small molecules (steroids, natural products, synthetic agents, environmental agents) and large molecules (peptide and protein agonists/antagonists, antibodies) with critical biomolecular targets in breast cancer (enzymes, receptors, DNA). Research projects and developmental programs of the proposal have several important multidisciplinary focuses in the areas of breast cancer etiology and therapy. Translational research objectives of the projects focus on integration and transfer of the basic sciences in these areas into clinical practice in the four year period of the P20 proposal. The major components of this P20 Program Development Grant are (1) description of the program leaders, (2) discussions on the investigators involved, their research activities, and developments of the program, (3) the development plan emphasizing new interdisciplinary projects in environmental factors in breast cancer and development of new breast cancer therapies, (4) budgets, and (5) supporting documents.